Bitcoin/Litecoin: Generate Signature

Bitcoin and Litecoin chains support the following signature kinds:

  • Psbt: Fully sign a PSBT, partially signed bitcoin transaction.

  • Bip322: Generates the signature for a generic message defined in BIP-322.

PSBT Signature

Property
Type
Description

kind*

String

Psbt

psbt*

Hex String

The hex encoded PSBT as shown below

externalId

(Optional) String

Sample request body

{
  "kind": "Psbt",
  "psbt": "0x70736274ff0100710200000001ca17431a33a13d3ef8bfb041c8546071f9d3a609abe3c91efbed83265e1426730100000000ffffffff02e803000000000000160014a40a65b46ff36c53f1afb8e35e25a4c0bcfc9979d6d1150000000000160014237ad8ba2ffd992f6ebc7ab388e77f00fc87d1c9000000000001011f54d6150000000000160014237ad8ba2ffd992f6ebc7ab388e77f00fc87d1c9000000"
}

200 response example

{
  "id": "sig-7dmih-01orr-xxxxxxxxxxxxxxxx",
  "walletId": "wa-36a0p-pdil7-xxxxxxxxxxxxxxxx",
  "network": "BitcoinTestnet3",
  "requester": {
    "userId": "us-3v1ag-v6b36-xxxxxxxxxxxxxxxx",
    "tokenId": "to-7mkkj-c831n-xxxxxxxxxxxxxxxx",
    "appId": "ap-341e6-12nj6-xxxxxxxxxxxxxxxx"
  },
  "requestBody": {
    "kind": "Psbt",
    "psbt": "0x70736274ff0100710200000001cd290edbff81f3762b1c9a6f6532f5f2d3d1e48a850d4285b8606bbceb96ee790000000000ffffffff020100000000000000160014a40a65b46ff36c53f1afb8e35e25a4c0bcfc99794d25000000000000160014237ad8ba2ffd992f6ebc7ab388e77f00fc87d1c9000000000001011fe425000000000000160014237ad8ba2ffd992f6ebc7ab388e77f00fc87d1c9000000"
  },
  "status": "Signed",
  "signatures": [
    {
      "r": "0xe10a3e24bb0b0a5feae39997d05b5d1ce0e123f78c979914ea3394962f7995f6",
      "s": "0x727190270d14e58acbcfa98a765fd4c50b51afb7d1ef8152cd79d562f28a1bbc",
      "recid": 0,
      "encoded": "0x3045022100e10a3e24bb0b0a5feae39997d05b5d1ce0e123f78c979914ea3394962f7995f60220727190270d14e58acbcfa98a765fd4c50b51afb7d1ef8152cd79d562f28a1bbc"
    }
  ],
  "signedData": "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",
  "dateRequested": "2024-01-10T19:15:21.572Z",
  "dateSigned": "2024-01-10T19:15:21.859Z"
}

Typescript Example with BitcoinJS

First install the BitcoinJS SDK. You can find the full documentation here: https://github.com/bitcoinjs/bitcoinjs-lib

Here a code sample to generate a signature via the Dfns TypeScript SDK:

import { networks, payments, Psbt } from 'bitcoinjs-lib'
import axios from 'axios'

const walletId = 'wa-6lbfv-9esgj-xxxxxxxxxxxxxxxx'
const wallet = await dfnsClient.wallets.getWallet({ walletId })
const publicKey = Buffer.from(wallet.signingKey.publicKey, 'hex')

const network = networks.testnet
const { address } = payments.p2wpkh({
  pubkey: publicKey,
  network,
})

const txid = '87872516c6e93f136fc6c493c7172596b11c695e27889de7532abffcac2a4b5e'
const n = 1
const utxo = (
  await axios.post(BITCOIN_NODE_URL, {
    jsonrpc: '2.0',
    id: 'gettxout',
    method: 'gettxout',
    params: [txid, n, false],
  })
).data.result

const balance = utxo.balance * 100000000
const amount = 1
const fee = 150

const psbt = new Psbt({ network })
psbt.addInput({
  hash: txid,
  index: n,
  witnessUtxo: {
    script: Buffer.from(utxo.scriptPubKey.hex, 'hex'),
    value: balance,
  },
})

psbt.addOutput({
  address: 'tb1q5s9xtdr07dk98ud0hr34ufdycz70exte2kehm2',
  value: amount,
})

psbt.addOutput({
  address,
  value: balance - amount - fee,
})

const res = await dfnsClient.wallets.generateSignature({
  walletId,
  body: { kind: 'Psbt', psbt: `0x${psbt.toHex()}` },
})

BIP-322 Generic Message Signature

Generates the signature for a generic message defined in BIP-322.

Request body

Property
Type
Description

kind*

String

Bip322

message*

String

The generic message hex encoded.

format

(Optional) String

Either Simple or Full. Defaults to Simple if not present. The formatted signature is returned in the signedData field in the response.

externalId

(Optional) String

Sample request body

{
  "kind": "Bip322",
  "message": "0x49206c6f76652044666e73"
}

200 response example

{
  "id": "sig-7dmih-01orr-xxxxxxxxxxxxxxxx",
  "walletId": "wa-36a0p-pdil7-xxxxxxxxxxxxxxxx",
  "network": "BitcoinTestnet3",
  "requester": {
    "userId": "us-3v1ag-v6b36-xxxxxxxxxxxxxxxx",
    "tokenId": "to-7mkkj-c831n-xxxxxxxxxxxxxxxx",
    "appId": "ap-341e6-12nj6-xxxxxxxxxxxxxxxx"
  },
  "requestBody": {
    "kind": "Bip322",
    "hash": "0x49206c6f76652044666e73"
  },
  "status": "Signed",
  "signature": {
    "r": "0x883613c2f19e4ab70f82c533950fb9060ac366a3a64d77950c89866dfe07c926",
    "s": "0x3fb815f34db5ebc9e97dee46500b75494717cb69adec5f01e17b4a58c50f9bfa",
    "recid": 1,
    "encoded": "0x3045022100883613c2f19e4ab70f82c533950fb9060ac366a3a64d77950c89866dfe07c92602203fb815f34db5ebc9e97dee46500b75494717cb69adec5f01e17b4a58c50f9bfa"
  },
  "signedData": "0x02483045022100883613c2f19e4ab70f82c533950fb9060ac366a3a64d77950c89866dfe07c92602203fb815f34db5ebc9e97dee46500b75494717cb69adec5f01e17b4a58c50f9bfa012103e6be69fe373e07962698243fb3d41b5b24e16a461866bd1813afcf9b53e1da6e",
  "dateRequested": "2024-10-25T17:47:48.068Z",
  "dateSigned": "2024-10-25T17:47:48.749Z"
}

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